Major leaps in year of discovery

It is not often we witness the greatest discovery of our time. The announcement in July that scientists had found the elusive Higgs boson, a subatomic particle that could explain some of the deeper mysteries of the universe, could easily be a contender for the prize.

For more than half a century, scientists have postulated the existence of a subatomic particle that creates an invisible force field that permeates the entire cosmos, imparting mass to matter but having no effect on other kinds of mass-less particles, such as photons of light.

When Peter Higgs, now a retired professor at the University of Edinburgh who will celebrate his 84th birthday in 2013, first dreamed of such an idea in 1964, few would have expected it to take this long to prove him right - or wrong.

The Higgs boson, or "God particle" as some have called it, is central to the Standard Model of physics. This is the model on which physicists have based their understanding of most of the fundamental forces of nature, from the weak electrostatic interactions between charged particles to the ultra-strong nuclear forces at the heart of the atom.

From what they knew about the Standard Model, theoretical physicists postulated there must be a missing subatomic particle which creates a field that interferes with the movement of other particles. Some types of matter find it difficult to move through this field, which means they have a greater mass than other kinds of matter that move through it more easily.

It is a deceptively simple concept but devilishly difficult to prove. In the end it required the combined effort of thousands of the brightest minds in science, several decades of painstaking experiments and a £2.6 billion ($5.1 billion) machine in the form of the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (Cern) in Geneva.

Early one July morning, the leaders of the two teams working on the key LHC experiments gave details of their findings to their enraptured colleagues. Despite the dizzying display of charts, it soon became clear from the reaction of the assembled cognoscenti that the LHC had done its job and found a particle that fitted the description of the Higgs boson.

"As a layman, I would say that I think we have it. Do you agree?" Rolf-Dieter Heuer, director general of Cern, asked the audience after the two presentations. The applause said it all.

Other scientists throwing high-fives in 2012 were the team at Nasa who successfully landed a sophisticated roving robot on Mars using the unconventional technique of lowering it onto the Martian surface from a "sky crane" about 8m overhead.

The successful landing on August 6 followed "seven minutes of terror", which started when the rover and its mother ship crashed through the Martian atmosphere at 21,243km/h. It took seven minutes and the combined effort of a heat shield, S-shaped flight manoeuvres, parachutes and retro-rockets to slow it down enough to carry out the final, delicate delivery by sky crane.

The Curiosity rover, a robot the size of a large car, is loaded with sophisticated instruments designed to analyse the make-up of the Red Planet. It could tell us whether the conditions were ever ripe on Mars for the origin and evolution of primitive extraterrestrial life-forms.

If life on Mars ever existed, it is likely to have long ago disappeared with the planet's rivers and oceans. An environmental disaster on Mars led many millions of years ago to the loss of liquid water.

The big question as 2012 ends is whether life on Earth is heading for something similar. The planet is in little danger of losing its water, but there is every sign that its climate is destined for a major upheaval in the coming decades.

In September, scientists reported the biggest loss of Arctic sea ice since satellite records began in 1978. Other scientists confirmed that melting ice sheets in Greenland and Antarctica were contributing to a marked rise in sea levels.

The amount of carbon dioxide released into the atmosphere from the burning of fossil fuels continued unabated in 2012, despite the global economic crisis. A separate team of researchers found evidence that the rising acidification of the oceans around Antarctica was beginning to corrode the shells of the tiny marine creatures at the base of the food chain.

If the Higgs boson was the greatest discovery of our time, then global warming threatens to be the greatest slow-motion disaster of our age.Independent